As quoted from a friend “the pressure has gone up because I have been turning it on and off at the mains so it fills the boiler each time, silly me, so need to reduce the pressure and leave the boiler on but don’t know how to do it”
Its apparently up at 3 bar which is into the red, and its a worcester 24i combi

a) Shouldn’t the pressure relief valve take care of this?
b) Can you manually do it on the boiler?
c) Is taking water out of a radiator an appropriate way of doing this? Although is this only possible with a rad key and water most likely going everywhere?

I assume its a combi.

Turning it on and off at the mains (not sure what you mean) shouldn’t do this but there is a tap under the boiler in the filling loop that could be open and will constantly fill the boiler and release excess water once too much pressure is built up. The pressure relief valve may take care of it but at a guess 3 is lower than its threshold. If the tap is open ion the filling loop it’ll just be filling up and emptying constantly

b – there is a tap somewhere in the boiler that will allow you to do it manually but if you don’t know whch one it is don’t turn just turn any nob.
c – yes, but you’ll need to drain off a bit of water.

Get a manula off the internet or call a plumber.

radiator ,it should not take a lot to reduce it

Drain tap at bottom of a rad – mine are square and can be done with a pair of pliers. Modern systems using a combi don’t have the traditional bleed valve at the top of the rad.

If you let too much out, there will be a grub screw on the boiler inlet pipe to let more back in.

Mine’s loses pressure, so I sometimes fill it – when I put too much in, I let it out of a downstairs rad.

My mate’s a plumber, so I know this is kosher.

do it from a radiator bleed valve water will come out be prepared to catch it- as it leaks the pressure decreases.
It will increase as it warms so check whether the pressure range is mine was 1 bar cold 2 bar hot iirc- you need to knwo which to set it too
if it increases again then get a plumber in etc. The pressure relief valve is set much higher 5-10 bar iirc to stop permanent damage rather to regulate actual pressure .

Last time my boiler hit 3bar+ is was due to a faulty expansion vessel…I was forever adding water to the system or letting water out until the expansion vessel was replaced. Does the pressure drop right back when the heating is turned off and everything cools down?

As the artist said ^^ there. Should be a minimum of one drain off valve on a downstairs pipe run or near a rad drop. Attach short length of hose or such like and into a bucket, a lot easier and cleaner than using bleed valves. Check pressure and top up if required then quick check for any air in rads. My combi blows off at 3 bar by the way. Hth

Thanks for all the replies. I found the lever on my combi, tried explaining it to friend but they say the boiler is in a cupboard and they can’t see underneath – either to find the lever or get a hand under to feel for it.
Their current plan is to call out a plumber but might see if I can pop over tomorrow afternoon to have a go.

If it’s a modern-ish installation then there should be an easy way to close the valve at each end of the fill loop. Then disconnect the feed end of the fill loop and stick in a bucket. Open boiler end of fill loop and watch the pressure drop to whatever number your boiler likes best, maybe 1 1/4 bar. Shouldn’t take more than a bucketful. Switching on and off at electric mains shouldn’t have an effect on the pressure though. Something else going on.